changing textbox border colour using javascript

问题:

I'm doing form validation. when the form input is incorrect i add a red border to the textbox:

document.getElementById("fName").style.borderColor="#FF0000"

this then gives me a 2px red border. what i want to do is if the user putas in a correct value to go back to the original border...

can someone tell me how i change the border size and colour in javascript

回答1:

Use CSS styles with CSS Classes instead

CSS

.error {
  border:2px solid red;
}

Now in Javascript

document.getElementById("fName").className = document.getElementById("fName").className + " error";  // this adds the error class

document.getElementById("fName").className = document.getElementById("fName").className.replace(" error", ""); // this removes the error class

The main reason I mention this is suppose you want to change the color of the errored element's border. If you choose your way you will may need to modify many places in code. If you choose my way you can simply edit the style sheet.

回答2:

document.getElementById("fName").style.border="1px solid black";

回答3:

Add an onchange event to your input element:

<input type="text" id="fName" value="" onchange="fName_Changed(this)" />

Javascript:

function fName_Changed(fName)
{
    fName.style.borderColor = (fName.value != 'correct text') ? "#FF0000"; : fName.style.borderColor="";
}

回答4:

You may try

document.getElementById('name').style.borderColor='#e52213';
document.getElementById('name').style.border='solid';

回答5:

document.getElementById("fName").style.borderColor="";

is all you need to change the border color back.

To change the border size, use element.style.borderWidth = "1px".

回答6:

I'm agree with Vicente Plata you should try using jQuery IMHO is the best javascript library. You can create a class in your CSS file and just do the following with jquery:

$('#fName').addClass('name_of_the_class'); 

and that's all, and of course you won't be worried about incompatibility of the browsers, that's jquery's team problem :D LOL

回答7:

If the users enter an incorrect value, apply a 1px red color border to the input field:

document.getElementById('fName').style.border ="1px solid red";

If the user enters a correct value, remove the border from the input field:

document.getElementById('fName').style.border ="";